1. Field of the Invention
The invention relates to a method of format change of a system for cutting a continuous web of corrugated board, which is conveyed in a conveying direction and has two lateral margins, into several continuous sectional webs of corrugated board, having a first and a second group of longitudinal-cutter tools, the method comprising the following steps: producing two first external longitudinal cuts and an intermediate first internal longitudinal cut in a web of corrugated board by a first group of longitudinal-cutter tools; disengaging at least a part of the first group of longitudinal-cutter tools from the web of corrugated board; engaging at least a part of the second group of longitudinal-cutter tools with the web of corrugated board; producing two second external longitudinal cuts and an intermediate second internal longitudinal cut in the web of corrugated board by the second group of longitudinal-cutter tools; producing an internal connecting cut which connects the first internal longitudinal cut and the second internal longitudinal cut and extends crosswise of the conveying direction; producing two external connecting cuts which extend crosswise of the conveying direction and respectively connect a first external longitudinal cut and a second external longitudinal cut.
2. Background Art
EP 0 894 583 B1 teaches a method of format changeover in a slitter/scorer machine in a corrugating plant. Provision is made for a first series of slitting tools and a second series of slitting tools, each consisting of a row of rotating, individually disengageable knives. For format changeover, all the knives of the first series of slitting tools disengage from the web of corrugated board with the exception of a single knife. Only the knife that remains engaged with the web of corrugated board makes a longitudinal cut further into an area of format change. Then this knife disengages too. Simultaneously a single knife of the second series of slitting tools moves into an active position so that the cut that is produced and the cut that extends into the area of format change overlap at their respective ends in the conveying direction. Sequentially, all the other knives of the second series of slitting tools engage with the web of corrugated board. Subsequently, the two longitudinal cuts that project into the area of format changeover are connected with one another by a crosscut that extends vertically of the conveying direction so that two continuous sectional webs of corrugated board originate which then move via a switch on to two different levels. Drawbacks of the known method of format changeover reside in that the entire corrugated board of the area of format change cannot be exploited in the subsequent job of cutting the sheets of corrugated board to size, thus being scrap. Given high conveying rates of for instance 300 m/min, format changeover areas of considerable length may result. Removing the area of format change from the web of corrugated board poses an additional problem. In dependence on the type of format changeover, the one-piece reject frequently has a width of more than half the width of the web of corrugated board. However, webs of corrugated board of inferior width are stacked subsequently so that the rejects frequently lead to inaccuracies in the job of stacking the sheets of corrugated board.